Comparator and equals()

Question

Suppose I need TreeSet with elements sorted with some domain logic. By this logic it doesn\'t matter order of some elements that doesn\'t equal so compare metho

Answer 1

There is no rule in Java which says that the hash codes of two objects must be different just because they aren't equal (so o1.hashCode() - o2.hashCode() could return 0 in your case).

Also the behavior of equals() should be consistent with the results from compareTo(). This is not a must but if you can't maintain this, it suggests that your design has a big flaw.

I strongly suggest to look at the other fields of the objects and use some of those to extend your comparison so you get a value != 0 for objects were equals() == false.